1. Technical Field of the Invention
The present invention generally relates to connectors and, more particularly, to zero-insertion-force connectors for mounting computer chips on circuit boards.
2. Description of the Prior Art
Zero-Insertion-Force (ZIF) connectors are commonly used in installing a central processing unit (CPU) on a circuit board. As the computing power of the CPUs is continuously enhanced, the pins of the CPUs are also significantly increased in numbers. The increased number of CPU pins requires the exertion of additional force so as to mount the CPU in a ZIP connector. Additionally, as customers continuously demand the electronic device to be even smaller, the ZIP connector has to be reduced in size as well. Together these present the following challenges to the conventional ZIP connectors.
As shown in FIG. 14, a ZIP connector for use in a notebook computer has a cam 70 configured at a side of the ZIF connector. When the cam 70 is rotated by a screw driver, the cover plate 71, with the CPU 60 on top of the cover plate 71, would horizontally slide relative to the body 72 of the ZIP connector, so that the pins of the CPU 60 could establish electrical contacts to the pin holes of the body 72. A user has to exert additional force to overcome the larger resistance resulted from the increased number of CPU pins. If too much force is exerted, a phenomenon shown in FIG. 13 would occur. As illustrated, if the cam 70 is not reliably positioned, the excessive force would cause a biased torque to the cam 70, displacing the axis of the cam 70 and resulting gaps S1 and S2 between the cam 70 and the body 72, and between the cam 70 and the cover plate 71, respectively. In the mean time, the body 72 and the cover plate 71 would suffer deformation, and the electrical contacts between the CPU pins and the pin holes would also be affected, or even disrupted.
In other words, if the cover plate 71 and the body 72 are made of plastic while the cam 70 is made of a metallic material, excessive force applied to the cam 70 when the cover plate 71 has already reached its terminal location would easily deform the cover plate 71 and/or the body 72. At least, the axial hole for the cam 70 would be widened or damaged.